I have been searching for quite a bit now, but no answers to my questions. I have this APC water temp gauge that's making me nervous. It reads anywhere from 230 to anything over 250 degrees. Many people here do not rely on the stock water temp gauge so that's out of question, but just in case, it is a tad below 1/2 constantly. I have the radiator fan mod on a stock radiator with aluminum AST. I do have an Autometer water temp gauge on it's way now because I just can't trust this CRAP brand. I know thi reading isn't normal, and I figured the engine would have blown up by now if that reading was right (correct?).

 

First off, high coolant temperatures doesn't mean your engine is going to explode. Now, high temperatures aren't necessarily good for the coolant seals and other various components of your car, but that's another issue.

Where is the sensor located for your APC gauge?

What are your ambient temps outside?

Does the stock temp gauge move at all when you see temps around 250F on your APC gauge?

 

The sensor is located at the AST tank.
Ambient temps= 96 degrees outside.
The stock temp gauge does move to exactly 1/2 when the APC gague reads 250+. This also including during traffic jams, going uphill and stepping on the gas for a short time.

 

Are your radiator fans coming on at all?

I'm not sure about that location for a temp gauge. It's quite possible that at exactly that location, the coolant temp is that hot. I know readings in the top of the water housing will read a little higher than the stock temp gauge location so it may be correct from its location.

Is the sensor actually located on a coolant line or is it tapped into the AST?

 

Yes, my fans are coming on, the probe is tapped to the AST. I attached a pic; it's the gold looking probe right at the AST. Where else would you tap to get a correct reading?

 

I see no AST.

 

Check this thread about coolant sensor locations:

https://www.rx7club.com/showthread.p...hreadid=226357

 

that is not the AST. for what i can see you don't have the AST. at 250F the stock gauge would be all the way up, the stock gauge is not reliable to have an accurate idea of your temp. but when is hot it will let you know. by the way i have a used fluidyne radiator i can send you using island wide express or you can pick it up. if interested shoot me a call at 787-598-2369

hugo

 

That is not the AST, it is the water pump housing. That is a fine location for the sender, but the indicated temperatures are clearly incorrect. FWIW, the stock fans come on at 221F if you are just idling with no accessories or anything turned on. What I would do is let the car idle, and make a note of what the readout of the gauge is when the fans come on. The stock gauge begins to move noticeably upward past halfway at 230F, and by 250F it should be at the upper white line. I'm not sure what the problem is, either its the gauge or the sender. It could be poor or degrading wiring is adding resistance to the circuit and sending the wrong readout to the gauge.

 

Sounds like your gauge is a POS. If your stock gauge isn't moving, when your gauge reads 250, its garbage.

 

Yea you also might want to position your intercooler so it's getting air from the duct too. I have a feeling the gauge is accurate enough. If it reads above 70F when you start the car from bone cold, I would say it's not accurate.

 

APC? You've already diagnosed your problem!

OMG....



Nothing changes - you get what you pay for. Toss it in the trash. The high end Autometer gauges are OK, but still not quality stuff. Talk about a marketing blitz...

All water temperature gauges are just about worthless since by the time they react to a heat problem the "event" that has caused them to spike in a 13B has usually already caused some damage. The last thing to heat up is the coolant.

Instead of spending hard earned money on cheesy gauges review your cooling system from head to toe. If EVERYTHING is in good working order and up to the task the last thing you'll need to worry about is an overheating engine, no matter what your mods are.

Even in a hot climate like Puerto Rico.

 

****! I feel like an idiot now. Oh well, I guess I'd better shut up and keep searching. I know APC is a **** brand, but the car came with them. Thanks anyway.

 

Why are there zip ties on the hose from the intercooler to the motor?

Also, what mix of coolant and water are you running in your system?

 

i have seen my stock gauge not move a milimeter when my autometer gauge went up to over 240 (it was really fast though so im good it also happened a while ago and i have been running strong) in anycase, ast tank is not the place to put water sensor, drill and tap in to water filler neck!

 

look closer at the picture

 

i dont get it, im just not seeing it

 

He has no AST. He's talking about the gold colored sending unit located in his filler neck.

 

Perhaps I have drank too much tonight, but what's the deal with the battery? Looks like there are two of them.........

 

there is no ast....... it is in the filler neck.........

 

thats his cable connected to the buss on the fuses

 

Zipties are holding a fan behind the intercooler. Don't know if this is a good idea or not, but I left it there. It turns on just as the fan mod.
Mix 40/60 coolant/water.

Hugo: I got your number. I'll be calling you to see how much you're asking for it.

 

APC, Sunpro, THEY ARE NOT ACCURATE

the insides are made of plasic and tin seriously man, don't screw yourself twice

 

ah, thanks.

 

All things considered equal the basic question is; Am I really running at this high temps. Well in my experience with piston cars, which make heat just like rotaries I try to look at each end. The electrical or gage and the real world side. Is the system building pressure like you might expect. Is the liquid boiling, at 250 you might get some idea. I would also think because I don't know with Mazda that the engine computer might be looking at the engine temp surely for fuel and timing management and not like seeing a 250 reading. Now it depends where its limit is with a G.M. car it might be around 250 but likely higher. I also would wonder How fast does the gage get to 250. We know that a cold engine can't get to 250 in under say.... 3 to 5 minutes. At least idling. Most Temp sensors are considered "indicators" not set up to give real accurate readings. How could they, there only sampling one area most often. I also would use another key indicator, if your fans are set up to come on at a set temp. look to see how that looks to the gage. I am going on and on I shut up now John